Robert Shaw was attacked by a bunch of men trying to rob him while off on his own reading. He fought off the attackers and chased the rest with a machete he retrieved from his Jeep.
During filming Robert Shaw said, "I'm seriously thinking that this might be my last film ... I no longer have anything real to say. I'm appalled at some of the lines ... I'm not at ease in film. I can't remember the last film I enjoyed making."
The film was originally to have been made in 1967, with Gregory Peck, Anthony Quinn and David Niven reprising their roles from I cannoni di Navarone (1961). However by the time the film was eventually made it was decided they were all too old for the sequel. They were even considered too old by some critics in the original film.
Harrison Ford later said, "It wasn't a bad film. There were honest people involved and it was an honest effort. But it wasn't the right thing for me to do."
The bridge was actually destroyed by partisans in 1942. Action of blowing it up was led by the engineer that built the bridge some years before. The engineer was shot later by Italians.